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V'UNTTED STATES PATENT OFFICE,

im WITT c. nnsxm, or NEW venin, N. Y.

CONSTRUCTION OF SUBMARINE TUNNELS.

SPECIFICATION forming part of Letters Patent No. 286,924, dated October 16, 1883 Application filed January 31, 1883. (No model.) n

.T 0 a/ZZ whom t may concern Be it known that I, DE WITT C. HAsKIN, of the city, county,'and State of New York, have invented certain new and useful Improvements in the Construction of Submarine Tunnels and other Works, of which the following is a full, clear, and exact description.

This invention relates to the construction of submarine tunnels and other y works or structures in which the work underprogress is carried on within an advanee'chamber or section charged with compressed air, and which is separated from the finished or partly-completed work in the rear by a bulk-head fitted with an air-lock constructed with opposite end doors to admit of the passage of men and materials from the one section to the other without impairin g or destroyingfthe higher pressure in the advance section under progress. Thus tunneling or excavating subject to compressed air in the portion or section of the work'under operation has the advantage of more effectually keeping` out water from entering said section or portion being excavated and 'of partially supporting the earth therein, also of facilitating the removal of much of the excavated material. An inconvenience, however, is experienced in the effect upon the health and comfort of the workmen by the too abrupt transition from the one section or chamber to the other of the tunnel or other structure be-` ing made by reason of the difference of atmospheric pressure in the chambers or sections separated by the bulkhead and single air-lock. My invention obviates this difficulty by using two or more air-locks arranged one in advance of the other, and chambers or divided sections which they connect, to correspond, together with means for supplying said chambers or sections with compressed air at different pressures-that is, in the one chamber as compared to the other-whereby the workmen may lirst pass through one of the locks into a compressed-air chamber of less pressure than is required where the work or excavation is being carried on, and afterward through another air-lock into a second or advance chamber of higher pressure, and which may be the working-chamber, or, in case of the same system being further extended, may be a preparatory chamber to the working one. By,

B, in course of construction.

thus graduating the pressure in the chambers, I moderate the effect which the sudden changes from normal atmospheric pressure to a much higher pressure produce upon the workmen.

Reference is to be had to the accompanying drawing, forming part of this specilication, which is a vertical longitudinal section of a submarine tunnel, in part, with my improvement applied.

A in the drawing indicates the perpendicular shaft down and up, through which ingress and egress is had to andr from the tunnel C represents an advance chamber, in which the work is being carried on, and D D' are bulk-heads separating it from and forming a second or rear chamber, C. These chambers communicate with cach other and with the portion of the tunnel immediate] y in connection with the shaft A by independent air-locks E E, which may be of the same construction for the passage of men and materials through them as the single air-locks atpresent in use inthe construction of submarine tunnels. Each of the chambers C C is supplied with compressed air, but of different pressures, q with air at a higher pressure than the normal one of the atmosphere, but of less pressure than that in the advance or working chamber C, where the`highest pressure is required, so that the workmen in passing from the portion ofthe tunnel immediately in connection with the shaftA into the chamber C will experience little or no inconvenience from the denser state ofthe air in said chamber, and will be prepared for the still higher pressure in the advance or Working `chamber O when passing into it. The chambers O C may be thus supplied with compressed air at the required difference of pressures by means of independent pipes Z b',

, connecting said chambers, respectively, either by passing through the bulk-heads or through the air-locks, with suitable compressors or compressed-air reservoirs outside of or above the shaft, orthe rear chamber, C', may be kept at the requisite intermediate pressure by a supply of waste air from the front chamber.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent- 1. The improvement in the art of constructd Thus the chamber C is supplied IcoV other, essentially as and for the purpose liere- 1o in set forth.

2. In the construction of submarine tunnels and other Works in which compressed air is l used as the medium to operate in, the combination of two or more chambers or sections of the work separated by partitions closing 'the same, air locks connecting `the saine, and means for supplying` said chambers with coinpressed air at different pressures, respectively, substantially as specified.

DE WITT c. HAsIKiN.

Vitnesses:

EDGAR TATE, ALFRED HoLCoMrE DAVIS. 

